Collective Structure inZr94and Subshell Effects in Shape Coexistence

Abstract

Based on results from a measurement of weak decay branches observed following the β- decay of 94Y and on lifetime data from a study of 94Zr by inelastic neutron scattering, collective structure is deduced in the closed-subshell nucleus 94Zr. These results establish shape coexistence in 94Zr. The role of subshells for nuclear collectivity is suggested to be important.

Selective properties of neutron transfer reactions in the 90Zr + 208Pb system for the population of excited states in zirconium isotopes

“…A selection of the populated states can then be achieved by setting different gates on the TKEL distribution, as illustrated in Ref. [16]. Applying the same procedure here, it turned out that the unknown γ transitions E γ = 213.7 keV in 90 Zr, and E γ = 215.8, 356.3 keV in 92 Zr, are more intense for the large Table 1 New γ transitions identified in the present 90 Zr + 208 Pb reaction.…”

“…All these later informations come from the different compilation articles (see text). To have a better insight into these new γ transitions, we compared, where applicable, the γ spectra with those obtained in the 40 Ca + 96 Zr reaction [16,37]. For this last reaction we have to keep in mind that the Zr spectra correspond to the undetected target-like ions, where the velocity vector has been evaluated assuming a binary reaction.…”

“…The segmentation of the anode into 40 rectangular sub-anodes allows to optimize the gas pressure in order to get the best nuclear charge resolution. The described detector system gives all the necessary information for the complete ion identification, which is performed via an event-by-event reconstruction of the trajectory inside the magnetic elements [16,22]. In this reconstruction, the ion trajectories after the quadrupole are assumed to be planar, as a consequence of the fact that the longitudinal dimension of PRISMA is much larger then the transversal one.…”

“…The total yields for pure neutron transfer channels have been already published in Ref. [16], where experimental data have been compared with the semi-classical model GRAZ-ING [2,17]. This model calculates the evolution of the reaction by taking into account, besides the relative motion variables, the intrinsic degrees of freedom of projectile and target, the isoscalar surface modes and the single-nucleon transfer channels.…”

Level Lifetimes in94Zr from DSAM Measurements following Inelastic Neutron Scattering

“…vs. 4.9(11) W.u. [7,8]. However, a strong M1 transition from the 1671-keV 2 + 2 level to the 919-keV 2 + 1 is still evident, 0.17 µ 2 n , thus this level remains a candidate for the lowest 2 + mixed-symmetry state, although alternative interpretations have been offered [8].…”